I'd tend to disagree with you, just because BM is much better at the pet holding aggro. In Surv and MM, even with a tanking pet, I still get the mobs/boss aggro. Never have the problem as BM.

I haven't had a single aggro issue while soloing since they added Glyph of Misdirection, really doesn't matter what spec you're in. And yes, MM is by far the best soloing spec for hunters since it has the most incoming healing simply by performing your rotation.

Some bosses have AoE that needs to be shared, were hunters will have a hard time (Morchok for example) or have abilities that only activates when there's 2 or more (pet included) inside the instance (Bone Spike Graveyard for example). Of the non-tank classes, I've found hunters very good when it comes to taking down multiple targets, mostly thanks to Glyph of Misdirection (multi-shot to win!). Warlocks feel a bit better, imo, when facing one target at a time and/or were the player will receive a lot of damage in short periods regardless of threat.

I always 'try' a raid with my DK first simply because I feel most comfortable and secure with her, not to mention the relatively high 'base-damage and healing' - without vengeance. While my Paladin could do almost as much if not more than my DK, the vengeance in lower tier content is just too low. We scale pretty well with vengeance, "unfortunately".

My Monk is ALSO very good at soloing stuff. We do high damage (very very high AoE especially) and have excellent healing like the above, great avoidance (the best). Imo, apart from Lay on Hands on my Paladin, Monks have probably the highest burst healing if you have enough healing spheres from Gift of the Ox lying around not to mention Expel Harm which becomes spammable below 35 % health. I have literally regained 90 % of my life by just moving to the right or left, quite a few times.

My druid isn't bad at all when it comes to soloing. It's just that our healing in Bear Form is too restricted or random (Dream of Cenarius). I also don't feel comfortable with 'relying' on avoidance on her, unlike my monk, on unmitigratable stuff.

I wish my Warriors Second Wind scaled based on the % of your max health. 0.5 % heal per second when above 70 % health. 1 % between 30-70 % and 3 % when below 30 % or something like that. Sometimes you'd have just needed those few seconds to regen behind your Shield Barrier(s) to survive the encounter. :/ Warriors feel very very sturdy however and deal great damage. I'm surprised at how much she can handle.

It depends on which one(s) you can play best in solo situations and what exactly you're attempting to solo. There's really exceptional players out there who can do really impressive things with a number of classes. But for mere mortals; Blood DK, Pally, Hunter, Warrior, Druid or Monk are all good choices.